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DTSTART:19700329T010000
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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Classification problem for effective structures -
Ekaterina Fokina (Vienna University of Technology)
DTSTART;TZID=Europe/London:20220609T133000
DTEND;TZID=Europe/London:20220609T143000
UID:TALK174830AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/174830
DESCRIPTION:In this talk we will review several approaches to
study the complexity of classifying effective stru
ctures up to isomorphism or another equivalence re
lation. Calculating the complexity of the set $E_\
\equiv(K)$ of pairs of indices corresponding to $\
\equiv$-equivalent computable structures from a fi
xed class $K$ is one of the approaches. One can us
e 1-dimensional or 2-dimensional versions of $m$-r
educibility to establish the complexity of such in
dex sets. According to this approach\, a class is
nicely classifiable if the set $E_\\equiv(K)$ has
hyperarithmetical complexity (provided the class $
K$ itself is hyperarithmetical). Another approach
is to classify structures on-the-fly. We call a cl
ass classifiable in this sense if we can uniquely
(up to a fixed equivalence relation) identify each
structure from the class after observing a finite
piece of the structure.
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:
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